News Ocean wildlife

Rising Ocean Temperatures and Tiger Sharks

The University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science has revealed the changes to tiger shark movements including timings and locations in the western North Atlantic Ocean. This is due to an increase of ocean temperatures. The sharks have become more vulnerable through moving outside of protected areas.

By Annette J Beveridge

Writer and conservationist Annette J Beveridge

Found in tropical and temperate regions, the tiger shark is one of the largest sharks in the world growing over 5 m in length. They weigh between 800-1500 pounds, and live up to 50 years. Tiger sharks are the only surviving member of the genus Galeocerdo.  The name tiger shark originates from the dark stripes running down its body but these fade as the shark matures.  Skin varies in colour from a blue or green hue and there is a light yellow underbelly. Females grow bigger than the males.

Tiger sharks are nomadic

Tiger sharks are guided by warmer currents. They remain in deep water moving along reefs but will move closer to the shore when following prey. These are aggressive predators, often circling prey, nudging it before establishing a full attack.  

Ocean wildlife

The Strange World of the Sunfish

by Annette J Beveridge

The oceans are filled with strange creatures and the sunfish is no exception. Using their large dorsal and anal fins to swim, they can move at speed when avoiding predators or, when they locate prey but are mostly seen simply drifting in the ocean currents. They are the heaviest of the bony fish weighing up to 1500 lbs – their size is impressive and they dwarf divers who are fortunate enough to swim with them. At birth, they have a back fin but this disappears as they mature. It appears to fold into the fish itself. Lying on one side as they manoeuvre through the ocean, these are spectacularly odd-shaped fish that have been mistaken for sharks when they emerge from the depths.

Descended from bony ancestors, the sunfish has cartilaginous tissues which is lighter than bone and as an adaptation, enables the fish to grow to an immense size. The teeth are fused – resembling a beak and they are unable to close their mouths. Sunfish have few enemies once they reach maturity but they do fall foul of boats when floating just beneath the surface and are at risk of becoming entangled in drift nets. Immature sunfish are predated on by sharks, whales. or sea lions.